I. Field of the Invention
The present invention relates generally to transit mixing concrete hauling vehicles and particularly to rear discharge types which include an appended discharge chute capable of lateral directional displacement to direct discharge of concrete in a desired direction. Specifically, the invention is directed to a mechanized chute control system to automatically and controllably rotate and position of the chute as desired.
II. Related Art
Concrete transit mixing or ready-mix trucks are widely used in the construction and paving industries for preparing and transporting concrete mixtures to desired construction sites where the concrete is discharged into prepared forms or other carriers. Discharge is normally accomplished by reversing mixing drum rotation so that concrete spills from the top drum charging opening. In order to guide concrete to prepared forms, equivalent molding structures, or other receiving containers, mixing trucks in commercial use today typically employ a main discharge chute having an ability to pivot both vertically and laterally. A chute may or may not have one or more extensions. In order to withstand stresses which are created by the discharge of heavy wet concrete (approximately 4,000 pounds or 1800 kg per yard), discharge chute components need to possess a great deal of strength and are typically made of rather heavy gauge trough-shaped metal segments.
The position of the chute typically must be adjusted often during discharge operations. Vertical adjustment is accomplished with the help of attached hydraulic cylinders, however, lateral operation of the chutes has been accomplished through manual positioning and the weight of the chute and the concrete material makes the positioning difficult during use. Additionally, chute operation requires virtually the full-time attention of one crew member who could more advantageously be accomplishing other tasks.
FIG. 1 presents, in schematic perspective illustration, a typical environment or context for which the present invention is designed. In that figure, a rear discharge transit mixer vehicle is depicted discharging concrete to one side of the truck. The truck generally designated 10 is supported as by wheels 12 connected by an axle assembly 14 mounted to a body frame 16 through a heavy duty suspension system 18. The transit mixing vehicle also includes a mixing drum 20 and a hopper for charging materials to be mixed at 21. The conventional discharge chute system includes a dispenser 22 which passes concrete from opening 23 through a transition segment 30 to an inclined chute system 24, including one or more U-shaped sections 26 tapering to a distal discharge end 28.
Elevation or vertical pivoting of the chute sections 26 is controlled and powered by a pair of fluid operated cylinders 36 and 38 linked thereto in a manner that also enables free rotation of the chute from side to side. This operation is typically manual and so, together with mechanized height adjustment, enables cement 40 to be placed in the desired location as at 42.
Once positioned, an air-operated chute lock is usually used to hold the chute in place. Additionally, a manually operated spring latched handle lock which uses a pin to align holes in moving and stationary parts may also be used.
Whereas prior systems have been successful, drawbacks include the need for constant attention by operating personnel in unlocking, making lateral adjustments and re-locking the chute in place. In addition, the chutes are heavy and, as is well known throughout the industry, care must be taken in the manipulation of such devices particularly during discharge operations. Accordingly, there remains a need for a hands-off mechanized system to automatically control the lateral positioning of the chute, to free an operator for other tasks and to provide better chute disposition control.
The present invention provides controlled motorized operation of the swivel or lateral chute swinging function of concrete discharge chute operations and is susceptible of remote or local control. The chute control system of the invention allows a full 180xc2x0+ lateral chute deployment range and provides inherent positive locking at all positions using an engaged transmission. A freewheeling manual override mode is included and a conventional latch lock is also provided. The system is designed to be compatible with many existing manual systems as a retrofit upgrade.
The system includes a fluid operated (preferably hydraulic) reversing motor connected to drive a suitable gear speed reduction and transmission system which includes a drive gear that engages a rotating chute swing plate gear which predicts and controls chute side-to-side orientation in response to operation of the motor. The system gears remain engaged after operation of the motor and this provides one positive locking mechanism. A manual spring-biased shaft latch lock also can be engaged. The gears can be disengaged to provide a manual or freewheeling override when desired. It is contemplated that the motor can be operated remotely from the cab of the truck or locally with controls at the rear of the vehicle.
This summary of the invention is intended not to limit the claimed subject matter, the scope of the invention being broader than any particular example and defined by the attached claims and their equivalents.